1. Field of the Invention
The present invention relates to a flame retardant asphalt composition. More specifically, the invention relates to a thermoplastic modified asphalt composition that includes a flame retardant coated with a silicone polymer.
2. Background
Asphalt is an excellent sealing and adhesive material. As such, asphalt is used extensively in the roofing industry. All sorts of roofing materials contain asphalt, including shingles and roofing paper.
Notwithstanding its excellent sealing and adhesive characteristics, asphalt has one major drawback. Asphalt is very combustible. As such, it is important to reduce the combustibility of an asphalt composition.
Many localities have regulations that require roofing materials to conform to certain standards. For instance, many such regulations require that roofing materials qualify as a Class A material under UL 790 or ASTM E-108 standards. These standards measure flame spread for noncombustible based decks and flame spread and brand penetration for combustible based decks.
Presently available flame retardant asphalt compositions have had difficulty in qualifying as a Class A material. Many of those that have passed include expensive and sometimes toxic ingredients. As such, the compositions are expensive and possibly dangerous.
Other presently available Class A flame retardant asphalt compositions include large quantities of noncombustible inert fillers. These materials are often heavy which may cause material handling problems.
Accordingly, a need exists to provide a thermoplastic modified asphalt material that is suitable for use on dwellings, schools and public facilities under the regulations now in force throughout the United States.